Google, Apple and Microsoft are duking it out on so many fronts assessing them can be a bit overwhelming. Meanwhile, the three companies have different business models, but increasingly bridge the enterprise and consumer markets.

In the end, these three look like every other vendor---they're selling you a stack of stuff.

The comparison between the three companies was the crux of a presentation at the Gartner Symposium in Orlando. On Monday, we looked at Apple and Google and their enterprise potential. Add Microsoft in the mix and the cloud and client collision is obvious. In addition, Google's acquisition of Motorola Mobility changes the client side equation. Why? Motorola puts Google into the tablet market and set-top box business.

The real stack battle comes in cloud services. On the cloud front, it's clear that the race is between Google and Microsoft on the consumer front. On the enterprise side, Microsoft has an ambitious cloud strategy.

Consider:

On the business and information front, Apple has iAd; Microsoft has AdCenter and Bing; and Google has AdSense. Advantage: Google.